Side view of a wolverine photographed by a remotely triggered camera at a snare established by another study, for the purpose of collecting hair from American martens. The snare is a black plastic base with bait, from which brass gun-cleaning brushes are attached. Photograph courtesy of the USDA Forest Service Pacific Southwest Research Station and Oregon State University

Side view of a wolverine photographed by a remotely triggered...

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Top view of a wolverine photographed by a remotely triggered camera at a snare established by another study for the purpose of collecting hair from American martens. Photograph courtesy of the USDA Forest Service Pacific Southwest Research Station and Oregon State University

Top view of a wolverine photographed by a remotely triggered camera...

Two more photographs of a wolverine lurking in the Tahoe National Forest were released Monday, extinguishing all doubt that the elusive predator exists in the wilds of California.

The wolverine pictures, taken from remote digital cameras by U.S. Forest Service researchers, mean the muscular carnivore with the almond-colored stripe has either avoided detection for three-quarters of a century or returned to the state after an epic journey.

An earlier image of what may be the same wolverine was captured inadvertently on Feb. 28 by a graduate student doing research on the wolverine's weasel family relative, the marten, and set off a near frenzy among giddy scientists and wildlife experts.

The dark photograph captured the animal from behind, showing off its distinctive stripe. The latest pictures, taken March 13, show the front of a wolverine that researchers believe is the same animal.

"We feel extremely lucky that this animal chose to visit another camera station," said William Zielinski, a research ecologist with the U.S. Forest Service's Pacific Southwest Research Station, who was working with Oregon State University graduate student Katie Moriarty when they captured the first wolverine image. "It's nice to have a head shot rather than just a rear shot."

Researchers, biologists and volunteers have fanned out over 155 square miles from the spot where the photo was taken in the forest north of Truckee, hunting for genetic material.

Cameras and "hair snares," which capture animal hair, were rigged and all suspicious-looking animal deposits were scooped up. Dogs trained to detect wolverine scat were unleashed in the forest by the Center of Conservation Biology in Washington.

Airplanes even flew overhead in an attempt to pick up signals from wolverines surgically fitted with radio transmitters during studies in Montana. Several wolverines with the internal transmitters have disappeared from study areas, but no signal was detected in the Tahoe area, Zielinski said.

The wolverine, which had not been documented in the Sierra since 1922, was believed by many to have vanished from California. There have been reported sightings through the years, but most were discounted as mistaken identity, Zielisnki said.

Skins of California wolverines at UC Berkeley and in several museums have been analyzed in the laboratory, a fact that has injected a note of urgency into the search for genetic material.

"Fortunately, enough previous work has been done on the genetics of wolverines that, if we can get a good enough sample, our colleagues think they can help us identify the population of origin for this individual," Zielinski said. "The historical population of wolverines that once existed in the Sierra Nevada had a very unique and distinct genetic signature. So it should be pretty clear if it's a remnant from that population."

It's important to researchers because the nearest population of wolverines is 900 miles away in Central Washington. That means the animal either migrated across an enormous distance or it's part of a small group of native wolverines that somehow evaded detection for the better part of a century.

The third possibility is that it is a fugitive from some captive population of wolverines. All three possibilities on the face of it seem unlikely, Zielinski said.

Although their habitat can stretch 500 square miles, the longest a single wolverine has been documented traveling was 83 miles in Norway, according to researchers.

The North American wolverine is the largest member of the weasel family, with adults weighing as much as 45 pounds. Stocky and muscular, it has a bushy tail and broad head that reminds people of a small bear.

Remarkably strong, with powerful jaws, wolverines have been known to kill much larger prey, but in North America they are mostly scavengers.

Wolverines were once fairly common throughout the northern regions of the United States, but they are now found mainly in the Northern Cascades in Washington, the Northern Rockies in Montana and Idaho, and in Alaska.